From Longman Dictionary of Contemporary Englishget crackingget crackinginformalFAST/QUICK to start doing something or going somewhere quickly I think we need to get cracking if we’re going to catch this train. → crack
Examples from the Corpus
get cracking• As far as I was concerned, it was time to shake our toes and get cracking.• It was here the Saltwater Fisherman players finally got cracking.• Then get cracking, drop me a line with your suggestions.• Come on! - get cracking. I want this whole house clean by the time I get back.• You'd better get cracking if you want to get to the airport by ten.• When Alf arrives we'll get cracking moving the furniture.• I'm going to the library - I've got to get cracking on this paper.• It's time you got cracking with your homework.• Get cracking you people! I want the whole house cleaned by four o'clock. 